TCP IP Bidirectional Communcation

I need a system that enables bidirectional data transfer between two systems using TCP IP communication. The ideal candidate should have experience in developing applications that enable seamless data transfer between different systems. Additionally, the project requires the use of platform-specific languages. The candidate should, therefore, be proficient in the relevant programming languages and platforms. As for security, I am open to suggestions on the appropriate level of encryption needed to secure the communication. Skills required are VB.Net Specific Only